In the last fiscal year we determined the etiology of this disorder. It is caused by mutations in the GLI3 zinc finger transcription factor and is thus allelic to the Greig cephalopolysyndactyly syndrome. In this fiscal year we plan to determine mutations in additional families to perform genotype-phenotype correlation, study the intracellular distribution and transcriptional activation properties, and study animal models of the disorder. Our preliminary data show that the truncated mutant GLI3 protein has nuclear tageting by using green fluorescent protein tagged GLI3. In addition, we will study patients with Greig cephalopolysyndactyly syndrome to determine the clinical and molecular overlap of these disorders. We have preliminary data showing that microdeletions may be a common cause of Greig syndrome.